1. Field of the Invention
The present invention generally relates to the control of printers attached to personal computers and, more particularly, to a technique for supporting all personal computer compatible printers in the environment of a professional office system. Specifically, the invention provides support for non-impact printers, such as laser printers and ink jet printers and other printers which do not respond to ANSI printable data for providing underscore, highlighting and overstriking.
2. Description of the Prior Art
The IBM Professional Office System (PROFS) is a licensed program designed to provide a comprehensive and easy-to-use set of office system and principal-support functions for business professionals. PROFS is a trademark of the IBM Corp The PROFS program is designed to operate in the Virtual Machine (VM) environment on IBM S-370 main frame computers. In particular, PROFS systems on multiple IBM 9370 computers have gained wide acceptance in departmental applications. For more information on the PROFS system, the reader is referred to "Using the Professional Office System, Version 2, Release 2", IBM Publication No. SH20-6797-01, Second Edition (June 1986).
The PROFS Personal Computer Support feature extends many of the powerful functions of PROFS to the IBM Personal Computer family. Used in conjunction with PROFS Version 2 at the host, this feature provides the intelligent workstation user with many PROFS functions using only the Personal Computer. For most users, a host PROFS session would be initiated only to transfer PROFS mail or other files or to use PROFS or VM functions that are not available at the Personal Computer.
Using this feature, the Personal Computer user sees a set of menus similar and complementary to those on the host PROFS system. The PROFS functions supported by this feature include in-basket processing of both notes and documents and viewing and processing of mail. PROFS Personal Computer Support also permits the user to store and mail Personal Computer files and to store groups of files on the host PROFS data base. These files can be DisplayWrite (TM of IBM Corp.) documents, spreadsheets, or other application reports. Documents created on DisplayWrite 1, 2 or 3 can be exchanged with PROFS users and PROFS Personal Computer Support users. For more information on the PROFS Personal Computer Support, the reader is referred to "Getting Started with the Professional Office System, Version 2 PC Support", IBM Publication No. SH20-6805-0, First Edition (February 1986).
The PROFS Personal Computer Support supports printers attached to Personal Computers by transferring ANSI files to the Personal Computer which are printed with a routine that understands the ANSI print controls. The problem is that ANSI controlled printing does not and can not allow non-impact printers (e.g., laser printers, ink jet printers and the like) to print bold characters. In addition, underlining is broken between characters and is difficult to see.
To better understand the problem, consider the following example:
This is a tast test.
This is but one line of text, but the ANSI printable data stream is in reality four lines, the first three ending with carriage returns but no indexing and the last ending with a carriage return with an index. The first line is the text itself; that is, "This is a tast test." The next line is the underscore for "is", followed by the third line with the overstrike for "tast", and finally the fourth line for the bold or highlight for "test". An impact printer can be easily controlled to perform several passes of the same line according to the ANSI standard. And, in fact, the PROFS Personal Computer Support includes a utility that accomplishes this result.
The problem is that non-impact printers such as laser and ink jet printers can not make multiple passes on the same line. The underscore, overstrike or highlight must be incorporated into the text as the text is formed. The problem then is to provide support for these printers which, while compatible with the personal computer and generally supported by most popular software run on the Personal Computer, are not currently supported by the PROFS Personal Computer Support feature.